The present invention relates to a vortex burner, and more particularly a vortex burner capable of burning either high or low Wobbe fuel gases.
Vortex burners are utilized in industrial type furnaces. A vortex burner is typically a nozzle mix burner which utilizes the tangential energy of the fuel gas, assisted by furnace draft, to entrain combustion air, mix the combustion air with the gas, and inject the burning mixture onto a radiant cup portion of the burner and along the furnace wall.
In the troubled energy situation we find ourselves in today, one cannot always rely on one particular type of gas for utilization as the fuel gas of a vortex burner. That is to say, at one period of time natural gas will be available while at another time a higher Wobbe gas such as propane or butane, will be all that is available.
The Wobbe index of a gas is a measure of the amount of heat released by the gas with a constant orifice, equal to the gross calorific valve of the gas in British thermal units (Btu) per cubic foot (ft.sup.3) at standard temperature and pressure divided by the square root of the specific gravity of the gas.
The conventional vortex burner typically has two #30 gas jets sized to obtain 1.25 MM Btu/hr rated capacity at 20 psig gas pressure and 0.2" W.C. draft per natural gas. The performance of such a vortex burner is acceptable for gases up to about 1600 Wobbe. Beyond a rating of 1600 Wobbe luminous tips and torching becomes objectionable. These objectionable features result from the reduced burner efficiency caused by the lower gas flows needed to obtain the same Btu release for the higher Wobbe fuels with high Btu content. Small gas jets and higher pressures are therefore necessary to obtain satisfactory performance on propane and other high Wobbe fuels, but the small orifices are unsuited for natural gas because of the high gas pressure required to obtain the rated capacity. However, having to change the spuds of a vortex burner so as to be able to burn fuels over a wide Wobbe range is very inefficient and costly.
Therefore, it would be quite desirable to those in industry utilizing vortex burners, to have such a burner which is capable of operating with gases over a wide Wobbe range without having the necessity of changing spuds.